Background/Purpose:

Ultrasound (US)-guided core needle biopsy (CNB) with or without concomitant fine needle aspiration (FNA) is a standard method for pre-operative evaluation of salivary gland tumors. Its application to the diagnosis of salivary gland lymphoma in patients with Sjogren’s syndrome (SS) has not been evaluated extensively. We sought to review our experience with these diagnostic techniques in SS patients with suspected salivary gland lymphoma.

Methods:

All patients of the Hopkins Sjogren’s Syndrome Center who underwent an US-guided CNB of a major salivary gland between 7/1/2009 and 5/30/2017 were identified through a computer database search. Twenty-six such patients had documented SS at the time of the biopsy and 25 underwent the procedure for evaluation of possible salivary gland lymphoma. All US-guided procedures were performed by radiologists with extensive experience in these techniques. CNB and FNA were done under real-time US guidance, using an 18 or 12 MHz linear transducer. The procedures included FNA at the discretion of the radiologist. FNA was generally done first with cellular material assessed for adequacy by a cytotechnologist present in the procedure room. The CNBs were obtained with an 18 gauge InRad needle. Patients were contacted one day after the procedure to assess for complications.

Results:

The indications for CNB included bilateral parotid gland enlargement (n=15), unilateral parotid (n=1) or submandibular gland (n=1) enlargement, discrete masses in the parotid (n=5) or submandibular (n=2) glands, and a sonographically abnormal intraparotid lymph node (n=1). The US-guided procedures included CNB in all 25 patients [mean number of CNB per gland = 2.15 (range, 1-4)], and FNA in 20 patients. Samples were sent for flow cytometry in 24 patients, using material obtained from CNB alone in 4, CNB and FNA in 18, and FNA alone in 2. Immunohistochemistry (IHC) was performed on 9 CNB samples with a prominent lymphocytic infiltrate. Final pathologic diagnoses were marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT; n=8), benign lymphocytic infiltrate (n=10), salivary gland tissue without an inflammatory infiltrate (n=6), and lymphoepithelial cyst (n=1). Flow cytometry revealed a clonally restricted cell population in 10/24 patients (B cell in 9, plasma cell in 1), of whom 7 were diagnosed with MALT lymphoma based on histopathology, IHC, and IgH gene rearrangement phenotyping of the B-cells. Flow cytometric samples were comprised of largely debris and thus without diagnostic utility in 4 patients (despite inclusion of tissue cores in 3); none of these 4 had MALT lymphoma on final diagnosis. No complications ensued from the procedures.

Conclusion:

US-guided CNB, coupled with flow cytometric analysis from one of the CNB samples and/or FNA, is a safe and effective method for differentiating benign from malignant lymphoid proliferation of the salivary gland in patients with SS. A clonally restricted B cell population on flow cytometry is not always indicative of lymphoma and must be corroborated by IHC and routine histopathologic analysis of CNB samples.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/diagnosis-of-salivary-gland-lymphoma-in-sjogrens-syndrome-utilizing-ultrasound-guided-core-needle-biopsies/